This invention relates to washing appliances and in particular wash chamber closure means. In particular, but not solely, the invention relates to dishwashers.
Dishwashers of the type described in WO 93/12706 and WO 98/33426 differ from conventional dishwashers in that a wash chamber and associated wash system is slidably mounted in the form of a drawer within a cabinet and the chamber is withdrawn horizontally to allow loading through the open top of the chamber. See present FIG. 1. A stacked two chamber single cabinet dishwasher as disclosed in WO 98/33426 is shown in FIG. 2. In dishwashers of this type where the wash chambers 4 are mounted as sliding drawers, the closing of the open top chambers prior to commencement of the wash cycle is more complicated than with conventional front loading or above-bench top-loading machines. It is undesirable to have users manually close a door to seal the open-topped wash chamber prior to pushing the extended xe2x80x98drawerxe2x80x99 back into the cabinet 2. It is preferable to have a closure 1 which is actuated by the action of retracting the wash chamber back into the cabinet. A wash chamber closure is held within the cabinet and when the chamber is retracted the closure sealably closes off the top of the chamber to contain wash liquid in operation. In WO 93/12706 the wash chamber closure is a lid of rigid unitary construction movably retained in the top of the cabinet and engaged by the wash chamber on retraction to be mechanically moved down onto the top of the wash chamber. A parallelogram linkage and cam mechanism can be employed to achieve this. In practice it has been found that other types of wash chamber closures may be satisfactory and may have better production economics.
A range of other such alternative closures is disclosed in WO 98/33426, including a rigid lid fixed in relation to the cabinet with an inflatable gasket attached Hereto being used to seal the lid to the wash chamber rim. The inflation device used to seal between the lid and wash chamber requires additional head space above the lid. This can be a consideration when two vertically stacked drawers are required to fit under a standard kitchen bench unit. Furthermore, the inflatable gasket may be ruptured by sharp objects, such as knives, that may be put into the dishwasher.
It is an object of the present invention to provide a dishwasher having a wash chamber closure which at least goes some way towards overcoming the abovementioned disadvantages or which will provide a further useful alternative.
Accordingly the invention consists in a washing appliance comprising:
a cabinet,
a wash system slidably mounted within said cabinet in such a manner that it may be withdrawn horizontally out of said cabinet for access thereto, said wash system including:
an open top wash chamber adapted to accommodate items to be washed, said wash chamber having a top peripheral rim,
a wash chamber closure mounted in the top of said cabinet, which closure covers the open top of said wash chamber on retraction of the wash chamber into said cabinet,
said closure being mounted in a horizontal plane in the top of said cabinet with a predetermined freedom of movement in the vertical direction,
at least one motor adapted to provide a linear reciprocating motion,
linkage means attached to said closure and connected to said at least one motor,
the motor and linkage means raising and lowering said closure in a vertical motion between a first position where the closure is in sealing engagement with said wash chamber rim and a second position where the closure is vertically spaced from the top of said wash chamber rim.